ST Loop

Motif Glossary

ST Loop

Definition

A motif of four consecutive residues and two H-bonds in which there is:

• Serine or Threonine (ST) at residue-4
• H-bond between side-chain OH of residue-4 and main-chain CO of residue-1
• H-bond between main-chain NH of residue-4 and main-chain CO of residue-1

Sub-categories

These encompass the following conformations for each of Ser and Thr:

• 2,3-αRαR (aka: type I or R-handed)
• 2,3-βRαL (aka: type II or R-handed flipped)
• 2,3-αLαL (aka: type I' or L-handed)
• 2,3-βLαR (aka: type II' or L-handed flipped)

Reference

Leader, unpublished

Comments

Members of the 2,3-αRαR sub-category of ST loops are also examples of ST staples.

Introduction AlphaBeta Loop Asx Motif Asx Turn Beta Bulge Beta Bulge Loop Beta Link Beta Turn BulgeLoop Motif Crown Bridge Crown Bridge Loop Nest Niche Schellman Loop ST Loop ST Motif ST Staple ST Turn